They may be referring to the tyre size. I recently went through this exercise for my 2018 SE, and eventually determined that the space-saver should be T135/80-D15 for this car. Earlier Jazz s/s tyres were T115/70-D14 or T125/70-D15 (or possibly others).
I think they are all 100mm PCD so should physically fit on the hubs. Again AFAIK the Jazz spigots are all 56.1mm std, though you'd need to check for sure.
I dare say you could get away with a 125/70-15 in reality if you stick to the speed limit and make sure it's fully inflated, though of course it's up to you to determine whether it would be OK.
I've just seen a T135/80-D15 on fleabay when checking back for what I had bought, there are a couple on there but not very common, e.g. items 254849298900 and 143915214536
